What everyone has already said, and I've also found it easier to pack/dig snow and push off (if I stay strapped in) when I flip over to my belly instead of trying to get up off my butt in a seated position.

Have you ever ridden in deep powder? cause it sounds to me like you have no idea?

Maybe less than a foot deep, that might work.
But basically, what you describe, would be like trying to do push-ups in the deep end of the swimming pool.

Maybe Jesus could after his stroll across the top of if, but I'm thinkin' even he, might have difficulties doin' push-ups.